Effects of unrecognized physiological residual arousal on emotional experience

This study investigated the effect of residual arousal on perceived positive and negative emotion, and the relationship between the valence of emotion and cardiovascular and cardiorespiratory reactivity. A total of 74 participants were randomly assigned to either a Residual Arousal (exercise‐induced) group or a No Residual Arousal (no exercise) group. Following the arousal manipulation, participants watched a video that elicited positive emotion and a video that elicited negative emotion. Within‐person differences revealed greater discrepancies between participants’ reports of positive and negative emotions in response to the videos, indicating that residual arousal caused stronger positive and negative emotions. With regard to physiological reactivity, participants in the No Residual Arousal group exhibited lower heart rate, respiration amplitude, and heart rate variability (LF /HF ratio) during the negative video than during the positive video, suggesting that the positive and negative videos had different influences on physiology. These results support the hypothesis that autonomic activation may be nonspecific with regard to the genesis of emotion, but once a person becomes emotional, physiological reactivity may differ between emotions.     

Subject-independent emotion recognition based on physiological signals: a three-stage decision method

Background

Collaboration between humans and computers has become pervasive and ubiquitous, however current computer systems are limited in that they fail to address the emotional component. An accurate understanding of human emotions is necessary for these computers to trigger proper feedback. Among multiple emotional channels, physiological signals are synchronous with emotional responses; therefore, analyzing physiological changes is a recognized way to estimate human emotions. In this paper, a three-stage decision method is proposed to recognize four emotions based on physiological signals in the multi-subject context. Emotion detection is achieved by using a stage-divided strategy in which each stage deals with a fine-grained goal.

Methods

The decision method consists of three stages. During the training process, the initial stage transforms mixed training subjects to separate groups, thus eliminating the effect of individual differences. The second stage categorizes four emotions into two emotion pools in order to reduce recognition complexity. The third stage trains a classifier based on emotions in each emotion pool. During the testing process, a test case or test trial will be initially classified to a group followed by classification into an emotion pool in the second stage. An emotion will be assigned to the test trial in the final stage. In this paper we consider two different ways of allocating four emotions into two emotion pools. A comparative analysis is also carried out between the proposal and other methods.

Results

An average recognition accuracy of 77.57% was achieved on the recognition of four emotions with the best accuracy of 86.67% to recognize the positive and excited emotion. Using differing ways of allocating four emotions into two emotion pools, we found there is a difference in the effectiveness of a classifier on learning each emotion. When compared to other methods, the proposed method demonstrates a significant improvement in recognizing four emotions in the multi-subject context.

Conclusions

The proposed three-stage decision method solves a crucial issue which is ’individual differences’ in multi-subject emotion recognition and overcomes the suboptimal performance with respect to direct classification of multiple emotions. Our study supports the observation that the proposed method represents a promising methodology for recognizing multiple emotions in the multi-subject context.

     

Psychophysiological effects of emotional responding to goal attainment

Effects of positive performance feedback on self-reported emotion and associated physiological responding and their relation to motivational engagement were investigated in an achievement context. To create a situation of self-relevant goal striving and goal attainment, appraisals of goal relevance and goal conduciveness were manipulated by presenting 65 female undergraduate students with a psychological test, followed by positive performance feedback. Emotional responding during the 1-min feedback showed elicitation of various positive achievement-related emotions associated with broad sympathetic activation (decreased pre-ejection period, increased cardiac output, and increased skin conductance and response rate). Individual-level emotion reports indicated distinct subgroups of participants experiencing primarily either interest, joy, pride, or surprise. Between-participants physiological reactivity was found to differ based on primary self-reported feelings. We discuss motivational antecedents and consequences in achievement-related emotions.     

Emotion recognition from physiological signals

Emotion recognition is one of the great challenges in human-human and human-computer interaction. Accurate emotion recognition would allow computers to recognize human emotions and therefore react accordingly. In this paper, an approach for emotion recognition based on physiological signals is proposed. Six basic emotions: joy, sadness, fear, disgust, neutrality and amusement are analysed using physiological signals. These emotions are induced through the presentation of International Affecting Picture System (IAPS) pictures to the subjects. The physiological signals of interest in this analysis are: electromyogram signal (EMG), respiratory volume (RV), skin temperature (SKT), skin conductance (SKC), blood volume pulse (BVP) and heart rate (HR). These are selected to extract characteristic parameters, which will be used for classifying the emotions. The SVM (support vector machine) technique is used for classifying these parameters. The experimental results show that the proposed methodology provides in general a recognition rate of 85% for different emotional states.     

Emotion recognition from physiological signals

Emotion recognition is one of the great challenges in human–human and human–computer interaction. Accurate emotion recognition would allow computers to recognize human emotions and therefore react accordingly. In this paper, an approach for emotion recognition based on physiological signals is proposed. Six basic emotions: joy, sadness, fear, disgust, neutrality and amusement are analysed using physiological signals. These emotions are induced through the presentation of International Affecting Picture System (IAPS) pictures to the subjects. The physiological signals of interest in this analysis are: electromyogram signal (EMG), respiratory volume (RV), skin temperature (SKT), skin conductance (SKC), blood volume pulse (BVP) and heart rate (HR). These are selected to extract characteristic parameters, which will be used for classifying the emotions. The SVM (support vector machine) technique is used for classifying these parameters. The experimental results show that the proposed methodology provides in general a recognition rate of 85% for different emotional states.     

Voluntary Control and Reactivity of Human Heart Rate

Factors in human voluntary heart rate control with and without external feedback were studied. Average voluntary heart rate control in the laboratory was comparable to the range of heart rates obtained during accelerative-decelerative ‘reactivity’ tasks in the laboratory and to heart rates obtained during various situation* outside of the laboratory. However, cardiac rate reactivity did not reliably predict voluntary control performance across subjects (Ss). With full instructions, Ss were able to increase but not decrease heart rate relative to resting levels before feedback was provided. With full-scale meter feedback. Ss could both increase and decrease heart rate relative to resting levels. Performance in Bidirectional control during feedback remained constant. The ability both to increase and to decrease heart rate transferred to the postfeedback. no-meter condition. Reversing the meaning of the Up and Down cue lights during post-feedback for half of the As had no deleterious effect on bidirectional heart rate control. The importance of physiological and situational constraints in Bidirectional heart rate control is discussed.     

A Multi-Response Analysis of Learned Heart Rate Control

Thirty college students were classified on the basis of cold-pressor blood pressure responses and then randomly assigned to one of three treatment groups. One group merely tracked a visual analog display of their heart rate (tracking group). A second group attempted to increase and decrease its heart rate without the visual display (no-feedback group). A third group attempted to increase and decrease their heart rates with the aid of the visual heart rate display (feedback group). Results indicated that the heart rate changes produced by both the feedback and no-feedback groups were significantly greater than those observed in the tracking group. There was no significant difference between the former two groups. Results also demonstrated that high cold-pressor reactors were able to produce significantly larger heart rate changes than the low reactor subjects. A correlational analysis of physiological responses accompanying heart rate change suggested that the response topographies of the high and low cold-pressor reactors differed as well. Finally, results indicated no relationship between coronary-prone personality characteristics, as measured by the Jenkins Activity Scale, and either cold-pressor reactivity or heart rate control performance.     

From emotion perception to emotion experience: emotions evoked by pictures and classical music.

Most previous neurophysiological studies evoked emotions by presenting visual stimuli. Models of the emotion circuits in the brain have for the most part ignored emotions arising from musical stimuli. To our knowledge, this is the first emotion brain study which examined the influence of visual and musical stimuli on brain processing. Highly arousing pictures of the International Affective Picture System and classical musical excerpts were chosen to evoke the three basic emotions of happiness, sadness and fear. The emotional stimuli modalities were presented for 70 s either alone or combined (congruent) in a counterbalanced and random order. Electroencephalogram (EEG) Alpha-Power-Density, which is inversely related to neural electrical activity, in 30 scalp electrodes from 24 right-handed healthy female subjects, was recorded. In addition, heart rate (HR), skin conductance responses (SCR), respiration, temperature and psychometrical ratings were collected. Results showed that the experienced quality of the presented emotions was most accurate in the combined conditions, intermediate in the picture conditions and lowest in the sound conditions. Furthermore, both the psychometrical ratings and the physiological involvement measurements (SCR, HR, Respiration) were significantly increased in the combined and sound conditions compared to the picture conditions. Finally, repeated measures ANOVA revealed the largest Alpha-Power-Density for the sound conditions, intermediate for the picture conditions, and lowest for the combined conditions, indicating the strongest activation in the combined conditions in a distributed emotion and arousal network comprising frontal, temporal, parietal and occipital neural structures. Summing up, these findings demonstrate that music can markedly enhance the emotional experience evoked by affective pictures.     

Controlling the emotional heart: Heart rate biofeedback improves cardiac control during emotional reactions

When regulating negative emotional reactions, one goal is to reduce physiological reactions. However, not all regulation strategies succeed in doing that. We tested whether heart rate biofeedback helped participants reduce physiological reactions in response to negative and neutral pictures. When viewing neutral pictures, participants could regulate their heart rate whether the heart rate feedback was real or not. In contrast, when viewing negative pictures, participants could regulate heart rate only when feedback was real. Ratings of task success paralleled heart rate. Participants' general level of anxiety, emotion awareness, or cognitive emotion regulation strategies did not influence the results. Our findings show that accurate online heart rate biofeedback provides an efficient way to down-regulate autonomic physiological reactions when encountering negative stimuli.     

Effects of joy and sorrow on pulse-graph parameters in healthy female college students based on emotion-evoked experiments

ObjectiveTo explore the effects of joy and sorrow on pulse-graph parameters in healthy subjects and analyze their potential effect to provide preliminary evidence that pulse diagnosis can identify human emotional changes.Design and interventionForty healthy female college students from Beijing University of Chinese Medicine were recruited. The emotion-evoking experiment was conducted to observe the effects of joy and sorrow on pulse-graph parameters, taking neutral emotion as a control. The experiment included the following criteria. (1) Emotions evoked and evaluated: the same subjects watched three emotional videos which were, respectively, neutral, joyful and sorrowful to evoke the corresponding emotions. They completed the “subjective emotion evaluation form” (SEEF) before watching each video (T₀), immediately after watching the video (T₁) and 15 min after watching the video (T₂) to conduct subjective emotion evaluation. Simultaneously, their heart rate, galvanic skin response and heart rate variability were collected with a 16-lead physiological recorder to conduct an objective evaluation of emotional arousal. (2) Collection of pulse-graph parameters: pulse-graph parameters of the subjects at T₀, T₁ and T₂ were collected with a pulse condition analyzer.ResultsWhen watching the joy video, the rapid ejection phase extended significantly, both the left ventricular diastole and the cardiac cycle shortened significantly. When watching the sorrow video, the left ventricular diastole extended significantly, the cardiac cycle showed an upward trend, and heart rate showed a downward trend.ConclusionJoy and sorrow have a certain effect on pulse-graph parameters of the subjects. The mechanisms may be that joy contributes to rapid ejection phase extension and a shortening of the left ventricular diastole and the cardiac cycle, while sorrow extends the left ventricular diastole. According to the theory of Traditional Chinese Medicine (TCM), the visceral functions can be mediated through human qi flow. Moderate joy and sorrow can promote, respectively, the smooth qi flow of the heart and the lung. However, excessive or long-term joy and sorrow can lead to disharmonious qi flow of the two viscera. Therefore, maintaining moderate emotions is beneficial to the physiological functions of the viscera. Great emotional fluctuations may damage the visceral functions. Future studies with effects of other emotions on pulse-graph parameters are warranted to determine the reliability of the association of emotions and pulse diagnosis.     

Affective Response to Color-Slide Stimuli in Subjects with Physical Anhedonia: A Three-Systems Analysis

Emotion-provoking visual stimuli were presented to college undergraduates identified as anhedonic or normal, based on their scores on the Physical Anhedonia Scale (Chapman, Chapman, & Raulin, 1976). The affective stimuli (35 mm color slides) were chosen to elicit a wide range of both positive and negative emotion, with emotional response assessed through affective judgments, viewing time, and monitoring of a variety of physiological systems (heart rate, skin conductance, and facial musculature). The experiment was successful in demonstrating differential emotional response in the two subject groups; anhedonic subjects reported a less positive response than control subjects to positive and neutral stimuli and showed no association between heart rate and the emotion content of the slides. Paradoxically, activity in the muscles of facial expression was greater in anhedonic than control subjects during the presentation of both positive and negative slides. No between-group differences were noted in the viewing-time measure. The results are discussed in the context of Lang's bioinformational theory of human emotion (Lang, 1984, 1985).     

The facilitative effect of facial expression on the self-generation of emotion.

Twenty-seven female undergraduates completed three tasks: (1) feel four emotions (happiness, sadness, anger, peacefulness); (2) express these emotions, without trying to feel them; and (3) feel and express clearly these four emotions. During each trial subjects pressed a button to indicate when they had reached the required state, and the latency from emotion cue to button press was measured. Heart rate, skin conductance and EMG from four facial sites (brow, cheek, jaw and mouth) were recorded for 15 s before and after the button press and during a baseline period prior to each trial. Self-reports were obtained after each trial. Facial EMG and patterns of autonomic arousal differentiated among the four emotions within each task. Shorter self-generation latency in the Feel-and-Show versus the Feel condition indicated the facilitative effect of facial expression on the self-generation of emotion. Furthermore, the presence of autonomic changes and self-reported affect in the Show condition supports the sufficiency version of the facial feedback hypothesis. The self-generation method employed as an emotion elicitor was shown to reliably induce emotional reactions and is proposed as a useful technique for the elicitation of various emotional states in the laboratory.     

Heart Rate Biofeedback and Cold Pressor Pain

This study addressed the relative contributions of self-regulated heart rate change and belief that heart rate is changing in an instructed direction to the perception of cold pressor pain. Forty male volunteers were each assigned to one of four combinations of increase or decrease heart rate instructions and increase or decrease feedback conditions. Subjects were given an initial 45-sec cold pressor test, 25 feedback trials, and a final cold pressor in which they were told to change their heart rate in the instructed direction, but without the aid of feedback. Subjects were instructed specifically that increased heart rate was associated with increased pain and decreased heart rate with decreased pain. The veridical groups (consistent instructions and feedback) showed appropriate heart rate changes during biofeedback training and parallel changes in heart rate and pain perception during the final cold pressor. The non-veridical (reverse) feedback groups showed no heart rate change during biofeedback training and no relationship between heart rate and pain perception changes during the final cold pressor test. EMG, respiration, and skin conductance data are presented, and several mechanisms are proposed to explain the physiological and subjective changes.     

Systolic Blood Pressure and Heart Rate Changes During Three Sessions Involving Biofeedback or No Feedback

Two groups of normotensive human subjects of both sexes received contingent feedback for increases or decreases in systolic blood pressure, and two additional groups received random (non-contingent) feedback or no feedback. Subjects in all groups served fur three 1-hr sessions separated by intervals of 24 hrs. Reliable decreases in blood pressure, reaching a maximum of 9.5 mm Hg at the end of the third session, were observed in the decrease group. No systematic changes in blood pressure were observed in the increase, random, or no-feedback groups. Heart rate increased or decreased in the groups receiving contingent feedback for increasing or decreasing blood pressure, respectively. It is concluded that contingent feedback is effective in lowering blood pressure and that decreases are augmented by extended training. The covariance of heart rate and blood pressure is discussed with reference lo curlier experiments.     

Effects of Alpha Feedback Training on Occipital EEG, Heart Rate, and Experiential Reactivity to a Laboratory Stressor

The intent of this study was to examine whether brief alpha biofeedback training would alter the degree of physiological and experiential stress evidenced in an aversive laboratory situation. While occipital alpha and heart rate were monitored, 36 subjects underwent 8 presentations of a warning tone preceding fingertip electric shock by 30 sec. Subjects were then placed into one of three treatments taking place in dim light with eyes open. Group 1 received 24 min of contingent feedback. Group 2 received an equivalent amount of non-contingent feedback and Group 3, a no-feedback control condition, listened to music. Following the treatment period, 12 additional tone-shock pairings were presented, equally divided between eyes-open and eyes-closed trials, also with and without continuation of the treatment period “signal” (i.e. contingent, non-contingent feedback, or music). The results revealed that, in general, enhanced alpha density was maintained by the contingent feedback group during the post-treatment aversive situation. However, the reduction in alpha suppression was not systematically accompanied by corresponding heart rate and self-report reductions in situational reactivity. It was concluded that alpha feedback training was not sufficient to produce a generalized relaxation to the aversive situation. Alternative accounts of the results, focusing primarily on independence of response systems, are discussed.     

Incidental emotions influence risk preference and outcome evaluation

Incidental emotions, which are irrelevant to the current decision, play a significant role in the decision‐making process. In this study, to investigate the influence of incidental emotions on behavioral, psychological, and electrophysiological responses in the process of decision making, participants were required to perform a monetary gambling task. During the selection stage, an emotional picture, which was chosen from the Chinese Affective Picture System and fell into one of three categories: negative, neutral, and positive, was presented between two alternatives (small/large amount of bet). The pictures were provided to induce incidental emotions. ERPs and self‐rating emotional experiences to outcome feedback were recorded during the task. Behavioral results showed that positive incidental emotions elicited risk preference, but emotional experiences to outcome feedback were not influenced by incidental emotions. The feedback‐related negativity amplitudes were larger in the positive emotion condition than in the negative and neutral emotion conditions for small outcomes (including wins and losses), whereas there was no difference between the three conditions for large outcomes. In addition, the amplitudes of P3 were reduced overall in the negative emotion condition. We suggest that incidental emotions have modulated both the option assessment stage (manifested in behavioral choices) and the outcome evaluation stage (manifested in ERP amplitudes) of decision making unconsciously (indicated by unchanged subjective emotional experiences). The current findings have expanded our understanding of the role of incidental emotion in decision making.     

Investigation of emotional and physiological recovery from tracking tasks

This study was conducted to investigate subjects' emotional and physiological recovery from tension. Subjects (N = 36) were assigned tracking tasks under three conditions: (1) the "Rest" condition in which subjects were not presented a task but asked to stay relaxed; (2) the "Non-performance" condition in which subjects were presented a task but were not required to perform it; (3) the "Performance" condition in which subjects were required to perform the task. We successively recorded eyeblinks, respiration, and heart rate in the pre-task rest period, during the task, and the post-task rest period. Subjects completed a questionnaire to rate their emotions for each period. Results indicated: that eyeblink rate decreased during the task under the non-performance and the performance condition; that respiratory rate and heart rate increased during the task in the performance conditions; and that during the post-task period these alterations showed a rapid recovery back to initial levels. As for subjective ratings of emotions, various changes were recorded in addition to recovery: "Disappointment" seemed to last long, "activation" recovered, and "tension" rebounded in the post-task period.     

Cognitive and Somatic Events Associated With Discriminative Changes in Heart Rate

In Experiment 1, 23 males were given instructions to think about anxiety-provoking cognitive events (n= 12) or relaxing cognitive events (n= 11) during 20 30-sec training trials. Significant pretrial-to-trial increases in heart rate were noted during anxiety instructions and significant pretrial-to-trial decreases in heart rate were detected during relaxation instructions. In Experiment 2,39 males were again given instructions to think about anxiety-provoking events (n= 19) or relaxing events (n= 20) during 20 30-sec training trials. In addition, half of the subjects in each of these instructional conditions were given digital heart rate feedback consistent with their instructions (e.g., were reinforced for heart rate increases during anxiety instructions), whereas half of the subjects in each instructional condition were given feedback inconsistent with their instructions (e.g., were reinforced for heart rate decreases during anxiety instructions). As in Experiment 1, significant pretrial-to-trial increases in heart rate occurred during anxiety instructions and significant pretrial-to-trial decreases in heart rate were noted during relaxation instructions. The type of feedback which subjects received had no effect on the heart rate changes. The heart rate changes in both experiments were generally accompanied by parallel changes in respiratory rate but not by changes in chin muscle tension. It appears that cognitive events can produce increases and decreases in heart rate which are comparable in magnitude to those noted during biofeedback.     

A longitudinal study of emotion regulation and anxiety in middle childhood: Associations with frontal EEG asymmetry in early childhood

We investigated whether brain electrical activity during early childhood was associated with anxiety symptoms and emotion regulation during a stressful situation during middle childhood. Frontal electroencephalogram (EEG) asymmetries were measured during baseline and during a cognitive control task at 4 ½ years. Anxiety and emotion regulation were assessed during a stressful situation at age 9 (speech task), along with measures of heart rate (HR) and heart rate variability (HRV). Questionnaires were also used to assess anxiety and emotion regulation at age 9. Results from this longitudinal study indicated that children who exhibited right frontal asymmetry in early childhood experienced more physiological arousal (increased HR, decreased HRV) during the speech task at age 9 and less ability to regulate their emotions as reported by their parents. Findings are discussed in light of the associations between temperament and development of anxiety disorders. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52:197–204, 2010     

Heart rate discrimination and heart rate control: a test of Brener's theory

Three experiments were conducted to examine predictions from Brener's theory regarding the relationship between autonomic discrimination and autonomic control. Experiment 1 examined the possibility that training subjects to discriminate their heart rates would enhance their skill at controlling that response. Twenty subjects participated in two sessions during which one group of 10 subjects received training (knowledge of results) on the Ashton discrimination technique. The second group performed the discrimination task but received no training. All subjects then took part in a third session of heart rate (HR) control (both increase and decrease) where half of each of the aforementioned groups received feedback during the control task, while the other half performed the HR control task without feedback. Results indicated that for the control of both HR increases and decreases, there was no significant difference between those subjects trained to discriminate their HR, and those who had received no training to discriminate HR. The second experiment investigated the hypothesis that training subjects with feedback to control their HR would enhance their capacity to discriminate their heart activity. Ten subjects participated in two sessions of HR control during which half the subjects received feedback training to increase HR. During a third session, all subjects underwent a test of discrimination ability using the Ashton technique, and no knowledge of results regarding performance was provided. Results confirmed the hypothesis. The final experiment in the series investigated the discrimination/control relationship within a problem-solving framework and used 20 subjects. Results confirmed the hypothesis that subjects forewarned at the time of discrimination training that a heart rate control task was to follow would perform better than 10 subjects receiving no forewarning of the task objective. This effect took place independently of cardiac discrimination ability. A second finding from this experiment was that subjects trained to discriminate heart rate were better able to increase heart rate than untrained subjects. This result contradicts that of Experiment 1, and reasons for this anomaly are discussed in detail.